Field
The present disclosure relates generally to an apparatus and methods for monitoring thermal runaway in a semiconductor device.
Background Art
Thermal runaway refers to a situation where an increase in temperature changes the conditions in a device in a way that causes further increase in temperature. This uncontrolled positive feedback often leads to a destructive result. In semiconductor thermal runaway, with increase of device junction temperature, heat generation from device increases faster than the heat can be removed. Thermal runaway in transistor devices can result in the parts getting damaged.
Some conventional methods can monitor on-chip temperature sudden surge or monitor on-chip current sudden surge. However, there is a thermal lag between temperature sensor location and transistor(s), which introduces thermal lag time. Also, monitoring on-chip temperature sudden surge requires pre-determination of location to place on-chip temperature sensor to minimize thermal lag time. On-chip thermal hotspot may not be the “leaky spot,” therefore, making the minimization of thermal lag time difficult. Also, by the time the on-chip temperature sudden surge is detected it is usually too late to prevent thermal runaway.
When monitoring on-chip current sudden surge, the measured current is a combination of dynamic current (current due to the activity of the device) and leakage current. Measuring on-chip current sudden surge has low sensitivity due to high level of dynamic current and also large current swings during the device's activities. Also, conventional methods do not define a threshold current value where the thermal runaway will occur.
The present disclosure will now be described with reference to the accompanying drawings. In the drawings, generally, like reference numbers indicate identical or functionally similar elements. Additionally, generally, the left-most digit(s) of a reference number identifies the drawing in which the reference number first appears.